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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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2dfb1e43f5
[BUG] When the anonymous block device pool is exhausted, subvolume/snapshot creation fails with EMFILE (Too many files open). This has been reported by a user. The allocation happens in the second phase during transaction commit where it's only way out is to abort the transaction BTRFS: Transaction aborted (error -24) WARNING: CPU: 17 PID: 17041 at fs/btrfs/transaction.c:1576 create_pending_snapshot+0xbc4/0xd10 [btrfs] RIP: 0010:create_pending_snapshot+0xbc4/0xd10 [btrfs] Call Trace: create_pending_snapshots+0x82/0xa0 [btrfs] btrfs_commit_transaction+0x275/0x8c0 [btrfs] btrfs_mksubvol+0x4b9/0x500 [btrfs] btrfs_ioctl_snap_create_transid+0x174/0x180 [btrfs] btrfs_ioctl_snap_create_v2+0x11c/0x180 [btrfs] btrfs_ioctl+0x11a4/0x2da0 [btrfs] do_vfs_ioctl+0xa9/0x640 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x1a/0x20 do_syscall_64+0x5a/0x110 entry_SYSCALL_64_after_hwframe+0x44/0xa9 ---[ end trace 33f2f83f3d5250e9 ]--- BTRFS: error (device sda1) in create_pending_snapshot:1576: errno=-24 unknown BTRFS info (device sda1): forced readonly BTRFS warning (device sda1): Skipping commit of aborted transaction. BTRFS: error (device sda1) in cleanup_transaction:1831: errno=-24 unknown [CAUSE] When the global anonymous block device pool is exhausted, the following call chain will fail, and lead to transaction abort: btrfs_ioctl_snap_create_v2() |- btrfs_ioctl_snap_create_transid() |- btrfs_mksubvol() |- btrfs_commit_transaction() |- create_pending_snapshot() |- btrfs_get_fs_root() |- btrfs_init_fs_root() |- get_anon_bdev() [FIX] Although we can't enlarge the anonymous block device pool, at least we can preallocate anon_dev for subvolume/snapshot in the first phase, outside of transaction context and exactly at the moment the user calls the creation ioctl. Reported-by: Greed Rong <greedrong@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CA+UqX+NTrZ6boGnWHhSeZmEY5J76CTqmYjO2S+=tHJX7nb9DPw@mail.gmail.com/ CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
147 lines
5.1 KiB
C
147 lines
5.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2007 Oracle. All rights reserved.
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*/
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#ifndef BTRFS_DISK_IO_H
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#define BTRFS_DISK_IO_H
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#define BTRFS_SUPER_INFO_OFFSET SZ_64K
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#define BTRFS_SUPER_INFO_SIZE 4096
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#define BTRFS_SUPER_MIRROR_MAX 3
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#define BTRFS_SUPER_MIRROR_SHIFT 12
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/*
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* Fixed blocksize for all devices, applies to specific ways of reading
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* metadata like superblock. Must meet the set_blocksize requirements.
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*
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* Do not change.
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*/
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#define BTRFS_BDEV_BLOCKSIZE (4096)
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enum btrfs_wq_endio_type {
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BTRFS_WQ_ENDIO_DATA,
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BTRFS_WQ_ENDIO_METADATA,
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BTRFS_WQ_ENDIO_FREE_SPACE,
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BTRFS_WQ_ENDIO_RAID56,
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};
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static inline u64 btrfs_sb_offset(int mirror)
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{
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u64 start = SZ_16K;
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if (mirror)
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return start << (BTRFS_SUPER_MIRROR_SHIFT * mirror);
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return BTRFS_SUPER_INFO_OFFSET;
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}
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struct btrfs_device;
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struct btrfs_fs_devices;
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void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info);
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void btrfs_init_fs_info(struct btrfs_fs_info *fs_info);
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int btrfs_verify_level_key(struct extent_buffer *eb, int level,
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struct btrfs_key *first_key, u64 parent_transid);
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struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
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u64 parent_transid, int level,
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struct btrfs_key *first_key);
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void readahead_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr);
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struct extent_buffer *btrfs_find_create_tree_block(
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struct btrfs_fs_info *fs_info,
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u64 bytenr);
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void btrfs_clean_tree_block(struct extent_buffer *buf);
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int __cold open_ctree(struct super_block *sb,
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struct btrfs_fs_devices *fs_devices,
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char *options);
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void __cold close_ctree(struct btrfs_fs_info *fs_info);
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int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors);
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struct btrfs_super_block *btrfs_read_dev_super(struct block_device *bdev);
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struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
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int copy_num);
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int btrfs_commit_super(struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
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struct btrfs_key *key);
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int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
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struct btrfs_root *root);
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void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
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u64 objectid, bool check_ref);
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struct btrfs_root *btrfs_get_new_fs_root(struct btrfs_fs_info *fs_info,
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u64 objectid, dev_t anon_dev);
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void btrfs_free_fs_info(struct btrfs_fs_info *fs_info);
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int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info);
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void btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info);
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void btrfs_btree_balance_dirty_nodelay(struct btrfs_fs_info *fs_info);
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void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
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struct btrfs_root *root);
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#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
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struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info);
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#endif
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/*
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* This function is used to grab the root, and avoid it is freed when we
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* access it. But it doesn't ensure that the tree is not dropped.
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*
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* If you want to ensure the whole tree is safe, you should use
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* fs_info->subvol_srcu
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*/
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static inline struct btrfs_root *btrfs_grab_root(struct btrfs_root *root)
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{
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if (!root)
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return NULL;
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if (refcount_inc_not_zero(&root->refs))
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return root;
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return NULL;
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}
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void btrfs_put_root(struct btrfs_root *root);
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void btrfs_mark_buffer_dirty(struct extent_buffer *buf);
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int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
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int atomic);
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int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid, int level,
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struct btrfs_key *first_key);
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blk_status_t btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
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enum btrfs_wq_endio_type metadata);
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blk_status_t btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio,
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int mirror_num, unsigned long bio_flags,
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u64 bio_offset, void *private_data,
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extent_submit_bio_start_t *submit_bio_start);
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blk_status_t btrfs_submit_bio_done(void *private_data, struct bio *bio,
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int mirror_num);
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int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
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struct btrfs_fs_info *fs_info);
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int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
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struct btrfs_root *root);
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void btrfs_cleanup_dirty_bgs(struct btrfs_transaction *trans,
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struct btrfs_fs_info *fs_info);
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void btrfs_cleanup_one_transaction(struct btrfs_transaction *trans,
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struct btrfs_fs_info *fs_info);
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struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
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u64 objectid);
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int btree_lock_page_hook(struct page *page, void *data,
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void (*flush_fn)(void *));
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struct extent_map *btree_get_extent(struct btrfs_inode *inode,
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struct page *page, size_t pg_offset,
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u64 start, u64 len);
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int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags);
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int __init btrfs_end_io_wq_init(void);
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void __cold btrfs_end_io_wq_exit(void);
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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void btrfs_init_lockdep(void);
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void btrfs_set_buffer_lockdep_class(u64 objectid,
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struct extent_buffer *eb, int level);
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#else
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static inline void btrfs_init_lockdep(void)
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{ }
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static inline void btrfs_set_buffer_lockdep_class(u64 objectid,
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struct extent_buffer *eb, int level)
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{
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}
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#endif
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#endif
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